Sol-gel technology for nano-textiles

1
A seminar
Sol-gel technology for nano-textiles
Pratikhya Badanayak and Dr. Jyoti V. Vastrad

2
Nanoparticles
• 1 and 100 nanometres (nm) in size
can help make materials lighter, more
durable, and more reactive.
• Small size large surface area
• Materials lighter
• More durable
• More reactive
• Retain natural properties
Why ?

4
Sol-Gel
poly-condensation
reactions
Liquid state Gel state
3D continuous network of
the sol particles
Stable dispersion of
colloidal particles/
polymers

5
Colloidal gel Polymer gel
Gels

6
Reactions
• Hydrogen cataion
/hydroxide anaion
Hydrolysis
• Loss of water
Condensation
Hydrolysis
M-OR + H2O = M-OH + ROH
Condensation
M-OH + M-OR = M-O-M + ROH
M-OH + M-OH = M-O-M + H2O

7
Mixing
Gel formation
Ageing
Washing
Drying
Xerogel Aerogel
Calcination
End product
Cryogel
Steps in sol-gel process

8
Alcogel Xerogel Aerogel Cryogel

9
• pH
• Solvent
• Temperature
• Time
• Catalyst
• Agitation
Factors affecting sol-gel process

11
Sol gel
applicatio
n in textile
finishing
Antibacte
rial
Anti-
wrinkle
Multifunc
tional
Flame
retardant
Water/oil
/soil
replant
Self-
cleaning
Photo-
catalytic
UV-
protectio
n

12
• Uniform & small sized
• At low temperature- high density glass
• Coating for films- easy
• Objects or films with special porosity
• Inorganic – organic composites
• Fiber extraction
Advantages of sol-gel process

13
• Not used- industrially
• Difficult- porosity
• High permeability
• Low wear-resistance
• Weak bonding
Dis-advantages of sol-gel process

Instruments for characterisation
Fourier Transform Infrared
(FTIR) Spectra
X- Ray Diffraction (XRD)

Transmission Electron
Microscope (TEM)
Scanning Electron Microscope
(SEM)

Energy
Dispersive X-ray
(EDX/S)
Thermo Gravimetric
Analysis (TGA)

Differential
Scanning
Calorimetry (DCS)
Particle Size
Analysis
(PCA)
UV-Vis
Spectroscopy

18
Synthesis and characterisation

Synthesis and Characterization of Sol–Gel Prepared
Silver Nanoparticles
• To investigate the effect of annealing temperature on the
synthesis and characterisation of silver nanoparticles
Ahlawat et al, 2014
19
Article - 1

Materials and methods
Precursor
AgNO3
TEOS
Catalyst
HNO3
Neutraliser
NaOH
Synthesis of silver–silica nanocomposites
AgNO3 + water, constant stirring under gentle heating
15.5mL of ethanol + 22.5mL TEOS stirring for 25 min at room temperature
Few drops of HNO3 and 10.5mL of water- stirred
20
Ageing -2 months
Dried in vacuum at 600°C for 3 h

Characterisation techniques
• XRD
Structural Analysis
• TEM
Morphological studies
• UV-Visible spectra
Optical absorption spectra
• FTIR
Unknown material
Heated at temperatures of 450°C and 550°C for half an hour
21

Result and discussion
Fig 1.
(a) The XRD spectra of the 1.25 wt.% AgNO3
doped silica sample without calcination
(b) The XRD spectra of the sample
calcinated at 450°C for 30 min and
(c) The XRD spectra of the 1.25 wt.% AgNO3
doped silica sample annealed at 550°C for
30 min
22
10.2 nm

Fig 2. (a) Absorption spectrum of AgNO3 doped silica samples without annealing and
(b) Absorption spectrum of 1.41 wt.% AgNO3 doped silica samples annealed at 550°C for
30 min
23

Fig 3. (a) FTIR spectra of the 1.25 wt.%
AgNO3 doped silica sample without
calcination
(b) FTIR spectra of the sample
calcinated at 450°C for 30 min and
(c) FTIR spectra of the sample
annealed at 550°C for 30 min
24

25
Fig 4. The TEM image of the sample annealed at
550°C
8-25 nm

Conclusion
26
• Size- 10.2 nm
• Temperature- formation of
nanoparticles
• Size distribution- 8 nm to 25
nm spherical

Synthesis of zinc oxide nanoparticles via sol-gel route and
their characterization
• To find a simple route to prepare nano ZnO particles via Sol-
Gel method and characterize the final product using several
techniques
Alwan et al, 2015
27
Article - 2

12.6g of zinc acetate dihydrate + 400 ml of double distilled water, continuous
stirring
600 ml of absolute alcohol, stirring
6ml of H2O2 added, stirred and dried at 80℃ = nano zinc oxides
Washed with double distilled water and dried at 80℃ in hot air oven
Nano synthesis
28

Physical and Physico – chemical Characterization
Morphology- SEM
Crstallinity- XRD
UV- Vis absorption- Spectro UV-
VIS Double beam UVD-3500
Composition- FTIR
29

Fig 5. XRD pattern of ZnO nanonanoparticls
30
58.3 nm

Fig 6. FTIR Transmition spectra of pure ZnO nanoparticls
31

Fig 8. UV-Vis optical absorption spectrum of ZnO nano particles
Fig 7. Shows the SEM image of
ZnO nanoparticles
32
100-200 nm

Conclusion
33
• Synthesis- successful
• Spherical shape (100-200nm)
• Uniform size

Antibacterial activity of capsaicin-coated wool
fabric
• To encapsulate capsaicin to produce an antibacterial
coating on wool fabrics by means of a sol-gel technique
Liu et al, 2013
35
Article - 3

Substrate
Double jersey knitted
interlock- 245 g/m2
Shrink proof-
(chlorine/Hercosett℗)
Coating
Octyltriethoxysilane (OTES), 16 M
3-glycidoxypropyltrimethoxysilane
(GPTMS), 16 M
Ethanol , 160M and Water, 100M
Tetraacetoxysilane (TAS), 1M- 30 min, 24 h
Capsaicin 0.01 and 0.04 mol/l
Wool - padded (one dip-and-nip, Werner
Mathis Laboratory Pad Mangle)
Air dried for 48 hours
Control-I (without capsaicin)
Control-II (uncoated original fabric)
Washed - Hydropal at 45°C
Fig 9. Structure of wool and
Capsaicin
36

Characterisation and testing
Optical density- (UV-Vis) spectrophotometer
Lower OD values indicate fewer bacteria
Surface morphology
SEM (LEO SEM S440, Germany)
Antibacterial activities
Gram-negative Escherichia coli (AATCC 11229, USA)
Fourier transform infrared (FTIR)
Burker Vertex 70 FTIR Spectroscope
37

Fig 10. Fourier transform infrared (FTIR) spectra of wool fabric and capsaicin-sol-gel
treated fabrics before and after laundry washes
(Sol-Cap-UW: unwashed capsaicin sol-gel coated fabric, Sol-Cap-1 W: capsaicin sol-
gel coated fabric-1 wash, Sol-Cap-3 W: capsaicin sol-gel coated fabric-3 washes,
ATR: attenuated total reflectance)
38

Fig 12. Morphology of untreated and coated fabrics and Escherichia coli after contact with fabrics
Fig 11. (a) Fabric sample placed on five inoculums streaks (b) Heavy bacterial growth (arrow
areas) underneath ‘control-I’ fabric (sol-gel coated) (c) No bacterial growth under capsaicin-
coated fabric
39

Fig 13. Optical density (OD) values of Escherichia coli cultures in soya broth medium incubated
with fabric samples at different time intervals
(Original: untreated fabric, Control-I: sol-gel coated without capsaicin, Fabric 1: coated with 0.01
mol/l capsaicin-sol gel, Fabric 2: coated with 0.04 mol/l capsaicin-sol gel)
40

Table 1. Antibacterial efficiency of capsaicin-coated wool fabric before and after
washing
Fabric sample Contact time
(h)
Bacteriagrowtha Antibacterial
activity
Original (Control-II) 24 Heavyb No effect
Sol-coated (Control-I) 24 Moderate to heavy
growthc
Insufficient effect
Capsaicin coated (Fabric 2) 24 No growthd Strong
1-wash (Fabric 2) 24 Slight growthe Limit of efficiency
3-wash (Fabric 2) 24 Slight growthe Limit of efficiency
aThe growth of bacteria in the nutrient medium under fabric specimen
bFull growth along streaks under the specimen
cCompare to heavy, growth reduced to half
dClear of bacteria growth
eSlight growth compared to no growth
41

Conclusion
42
• (Silica- capsaicin)- Prolonged
antibacterial effect
• Reduced- antibacterial
efficiency, capsaicin- attached

Simultaneous dyeing and anti-bacterial
finishing of textile by sol-gel technique
• To incorporate basic dyes and antimicrobial compound in the
sol-gel coating of cotton and polyester cotton blend
Kale et al, 2016
43
Article - 4

Material
Plain weave cotton (12×17/cm)
Plain weave polyester-cotton (P/C)
Chemicals
Tetraethylorthosilicate (TEOS)
Glycidoxypropyltrimethoxysilane
(GPTMS)
Ethanol (98% pure)
Hydrochloride acid (HCl)
Cetyltriammoniumbromide (CTAB)
Sodium Lauryl Sulphate
Dye- Coracryl Violet C3R
44

Sample preparation
• 50ml ethanol, 34.20ml TEOS, 3.8ml
Glycidoxypropyltrimethoxysilane (GPTMS) and
12ml HCl= 100ml
• Magnetic stirrer for 24hours at room
temperature
• CTAB and 10 gpl Coracryl Violet C3R dye
Sols
• Padded- 2 dip 2 nip method with 70%
expression for cotton and 60% for P/C
• Air dried and cured in oven at 120°C for 1 hour
• Soaped at 40°C for 2 hours by 10gpl Sodium
Lauryl Sulphate at neutral pH
• Washed and dried
Application
45

Testing
• Computer Color Matching System (Spectra Scan
5100+)
Colour strength
• Wash, light and rubbing- ISO 105 C10, ISO 105-A02
and ISO 105 X-12 respectively
Fastness
• AATCC Test 100-2004 and the colony-forming units
(CFUs) -Lapiz Coloney Counter
Antibacterial activity
• 10 wash cycles- with detergent (3% owf) at 40°C in
a Rota dyer
Wash Durability of Finish
• Tensile strength and elongation- ASTM D 5034-95
• Stiffness-ASTM D1388-08(2012)
Mechanical Properties
Characterisation
• SEM- JEOL JSM 6380LA, JEOL ltd. JapanSurface morphology
46

Fig 14. Plot of Colour strength of the fabric samples
47
CATB

Conce
ntratio
n of
CTAB
(gpl)
Cotton P/C
Rubbing
Fastness
Wash Fastness Light
Fastne
ss
Rubbing
Fastness
Wash Fastness Light
Fastne
ss
Dry Wet Staini
ng
Colour
Chang
e
Dry Wet Staini
ng
Colour
Chang
e
0
(Contr
ol)
4-5 4 4-5 2 3-4 2-3 2 3 3 3-4
10 2 2-3 2-3 2-3 2-3 2 2-3 2-3 2-3 2-3
20 2 2-3 2 2-3 2-3 2 2-3 2 2-3 2-3
48
Table 2. Fastness properties for dyed and CTAB finished Cotton and P/C
fabric with different concentration of CTAB

Conce
ntrati
on of
CTAB
(gpl)
P/C Cotton
Before Wash After 10 washes Before Wash After 10 washes
Number of
Colonies
after
Reduc
tion
in
coloni
es
(%)
Number of
Colonies
after
Reduc
tion
in
coloni
es
(%)
Number of
Colonies
after
Reduc
tion
in
coloni
es
(%)
Number of
Colonies
after
Reduc
tion
in
coloni
es
(%)
0 hrs 24 hrs 0 hrs 24 hrs 0 hrs 24 hrs 0 hrs 24 hrs
0
(Contr
ol)
0.30x
105
1.84x
105
Nil 0.92x
105
3.34x
105
Nil 1.53x
105
13.3x
105
Nil 1.73x
105
15.3x
105
Nil
10 2.73
x105
0.28
x105
89.74 3.67x
105
0.92x
105
74.93 2.00x
105
0.326
x105
83.7 3.52x
105
0.99x
105
71.88
20 2.20x
105
0.024
x105
98.80 3.98x
105
0.72x
105
81.91 1.63x
105
0.075
x105
95.3 2.09x
105
0.42x
105
78.46
Table 3. Antibacterial activity for dyed and CTAB finished fabric with CTAB for
different concentration of CTAB against S.Aureus
49

Fig 15. Colonies against S.aureus
50

Table 4. Mechanical properties of dyed and CTAB finished fabric for different
concentration of CTAB
Conce
ntratio
n of
CTAB
(gpl)
P/C Cotton
Tensile
Strength (Kgf)
Elongation
(%)
Bendin
g
Length
(cm)
Tensile
Strength (Kgf)
Elongation
(%)
Bending
Length
(cm)Warp Weft Warp Weft Warp Weft Warp Weft
Untrea
ted
119.7 63.3 59.7 32.5 1.19 63.9 33.36 11.46 17.07 2.57
0
(Contr
ol)
117.8 52.8 52.1 32.6 1.21 57.7 30.55 14.21 19.23 2.64
10 116.8 51.5 54.5 35.2 1.23 56 29.04 15.47 19.87 2.71
20 115.8 50.43 55.7 36.1 1.53 53 24.63 16.10 20.04 2.81
51

Conclusion
53
• Dyeing and anti-bacterial-
successful
• Fabric- soft

Phosphorus-Silica Sol-Gel Hybrid Coatings for Flame
Retardant Cotton Fabrics
• To investigates the use of organic-inorganic sol-gel coatings based on
silica and phosphorous compounds for providing cotton fabrics with
flame retardant features
Rosace et al, 2017
54
Article - 5

100% scoured & bleached cotton fabric
Diethylphosphatoethyltriethoxysilane (DPTS)
3-aminopropyltriethoxysilane (APTES)
1-hydroxyethane 1,1-diphosphonic acid
Melamine
Urea
Hydrochloric acid
Sodium hydroxide
Ethanol
N-hexakis-methoxymethyl- [1,3,5] triazine-2,4,6-triamine (MF)
Materials
Functional finishing of cotton fabric
APTES and DPTS were hydrolysed with HCl in deionized water,
vigorous stirring for 10 h at room temperature
55

56
3 Solutions containing the MF were prepared by adding 0.002,
0.004 and 0.006 mol of MF (MF30, MF60, MF90 respectively) in
deionized water
Molar ratios of APTES (0.06, 0.12 and 0.25 M) and DPTS (0.25 M)-
DPTS-APTES05, DPTS-APTES1 and DPTS-APTES2
In DPTS sol containing MF 0.002, 0.004 and 0.006 mol, DPTS-MF1,
DPTS-MF2, DPTS-MF3
Cotton samples by a pad-cure-method (Werner Mathis padder)
Dried at 80°C for 2 h, then cured at 150°C for 2 min in a laboratory
oven

57
Burning behaviour
Flammability Tester Model
7633E
ASTMD 1230
Thermogravimetric analyses
TA Instruments Q500 thermobalance
Characterisation

Result and discussion 58
Fig 17. TG curves of pure and treated cotton fabrics in nitrogen: Weight/% vs
Temperature/°C

59
Sample Residue at
360°C [%]
Residue at
750°C [%]
Untreated
cotton
14 2
DPTS 53 23
APTES 41 8
DPTS-APTES05 56 27
DPTS-APTES1 57 22
DPTS-APTES2 60 21
MF30 39 3
MF60 37 5
MF90 31 4
DPTS-MF1 60 20
DPTS-MF2 60 29
DPTS-MF3 60 33
Sample Total
burning
time [s]
Burning
Rate [mm/s]
Residue
[%]
Untreated
cotton
33 10 -
DPTS 35 6 37
APTES 24 7 33
DPTS-APTES05 21 10 60
DPTS-APTES1 20 9 48
DPTS-APTES2 24 8 53
MF30 150 10 27
MF60 51 12 19
MF90 28 8 20
DPTS-MF1 17 10 79
DPTS-MF2 19 8 68
DPTS-MF3 23 7 66
Table 6. Collected data of untreated
and treated fabrics by flammability
tests
Table 5. TGA data of untreated and
treated cotton fabrics in air

60
Table 7. Flammability data
Sample Total burning time [s] Residue [%]
Untreated cotton 36 -
Only DPTS (O_D) 24 25
Only bisphosphonate (O_P) 23 10
Only melanine (O_M) 25 2.0
Only urea (O_U) 36 2.0
DPTS- bisphosphonate
combi (D_P)
38 40
DPTS- melamine combi
(D_M)
15 24
DPTS- urea combi (D_U) 25 22

Conclusion
61
Hybrid phosphorus-silica nano sol
• Thermal stability
• Flame retardance

Silk fabrics modification by sol–gel method
• To evaluate the potential of sol–gel hybrid coatings for the
functionalization of silk fabrics
• To improve their performances in terms of abrasion resistance
Ferri et al, 2016
63
Article - 6

Sol-synthesis
• Tetra-ethyl-ortho silicate (TEOS)
• HCl
Precursor
Catalyst
• 3-glycidoxypropyltrimethoxysilane, GLYMO
• Hexadecyltrimethoxysilane, HDTMS
• Octyltriethoxysilane, OctTEOS
• 1H,1H,2H,2H-perfluorooctyltriethoxysilane, XF8
Alkyl/ fluro-
alkyl
functionlised
Si-alkoxide
• Water (Triton-X 100) or Isopropanol (stoichiometric
water)
Solvent
(surfactant)
• 20 min stirring- addition of functionlised alkoxide –
stirring 4 hrs
• pH= 2
Parameters
64

Composition of sols
65
3-glycidoxypropyltrimethoxysilane, GLYMO
Hexadecyltrimethoxysilane, HDTMS
Octyltriethoxysilane, OctTEOS
1H,1H,2H,2H-perfluorooctyltriethoxysilane, XF8

Fabric
54 g/m2 un-dyed twill Silk
Methods
• Fabric stiffness- Hanging loop test
• Abrasion resistance -James Heal (Halifax, UK) Mini-Martindale
tester
• Oil-repellency- UNI ENISO 14419.2010
• Tensile test- Universal Testing Machine 112
66

0
5
10
15
20
Hangingloop test - l -l0 Untreated
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
Fig 18. Values of d=l-l0 from hanging loop test for untreated
silk and coated fabrics
67
Isopropynol
Water
3-glycidoxypropyltrimethoxysilane, GLYMO

Table 8. Abrasion resistance of treated samples
Cycles 5000 7000 8500
S1 × × ×
S5 × × ×
S6 √ √ ×
S7 √ √ √
S8 × × ×
S9 √ √ √
S10 √ √ √
Fig 19. Appearance of samples after abrasion cycles:
(a) untreated silk after 8500 cycles,
(b) S1 after 2500 cycles,
(c) S5 after 2500 cycles,
(d) S6 after 8500 cycles,
(e) S9 after 8500 cycles, and
(f) S10 after 8500 cycles
68

Table 9. Static contact angles (α±3°) of oils drops on the S10 coated silk samples
Degree OIL α (°)
1 Mineral oil 125
2 65:35 mineral oil: hexadecane 124
3 Hexadecane 121
4 Tetradecane 123
Fig 20. Maximum load and elongation at
break (%) for coated silk fabrics samples
* TT indicates the samples that were
thermally treated at 100°C
69
144
146
148
150
152
Load at Break (N)
Load at
Break (N)

Conclusion
70
• Hybrid sol–gel silica coatings-
effective
• Properties- some enhanced
and some reduced

UV Photo-Stabilization of Tetrabutyl Titanate for
Aramid Fibers via Sol–Gel Surface Modification
• To investigate the effect of TiO2 coating on photo-stability of
aramid fibers
Xing and Ding, 2016
71
Article - 7

Preparation of TiO2 sols
Precursor- Tetrabutyl titanate (TBT)
Catalyst- HCl and Acetic acid
Water
Stirring for 10min at room temperature
Materials and coating
• 1.47 dtex Kevlar fiber-
Tensile strength- 27.21 cN,
Elongation at break -3.4% (DIN EN ISO 527-1-1996)
Elastic modulus -648.7 cN/dtex
• Dipped and treated at room temperature for 30 min and then dried
and annealed in a vacuum oven at 80°C for 30min, then backed for
80°C & 500°C for 2 h.
72

Characterisation
UV exposure conditions Photo-ageing procedures (UV lamp) for 24h
Fiber tensile test Model XQ-1 fiber tester
Microscopic analysis
Composition (Crstalinity)- XRD
Nanoscopic damage on the fiber surface- SEM
Chemical composition- SCALAB MK-II X-ray Photo
Electron Spectroscopy (XPS)
73

Fig 21. XRD patterns of nanosized TiO2 baked at different temperatures for 2 h
74
25 nm

Fig 23. Tensile strain of aramid
fibers as a function of UV exposure
time
Fig 22. Tensile strength of aramid
fibers as a function of UV exposure
time
75

Fig 24. SEM images of
surface of aramid
fiber.
(a) Uncoated,
exposure for 0 h
(b) Uncoated,
exposure for 156 h
(c) Uncoated,
exposure for 156 h
(the latitudinal
crack fracture)
(d) Fiber fracture after
tensile test, before
exposure
(e) Coated, exposure
for 0 h
(f) Coated, exposure
for 156 h
76

Table 10. Deconvolution Analysis of C1s Peaks for Uncoated and Coated Aramid
Fibers
Sample Functional group ratio (%)
C-C C=O COOH
Uncoated fiber, 0 h 77.0 2.7 0
Uncoated fiber, 48 h 57.1 2.6 7.0
Uncoated fiber, 156 h 44.5 6.7 11.1
Coated fiber, 0 h 58.4 3.9 4.0
Coated fiber, 48 h 42.1 4.7 4.7
Coated fiber, 156 h 33.55 6.07 9.9
Table 11. XPS Spectra of Ti 2p Region for Coated Aramid Fibers with Various UV
Exposures
Sample Binding energy (eV)
Ti 2p3/2 Ti 2p1/2 Gap
Coated fiber, 0 h 458.4 464.0 5.6
Coated fiber, 48 h 458.9 464.5 5.6
Coated fiber, 156 h 459.2 464.9 5.7
77

Conclusion
78
• Coated fabric-
• Photo stability
• Protects- latitudinal
cracks
• Slow down- acylamide
bond

Hemp Fibres Modification by sol-gel Method for Polyolefin
Composite Filling
• To implement silica nanolevel coating on fibres surface
without compromising the mechanical properties
Zelca et al, 2017
79
Article - 8

• Precursor - TEOS- 0.09 to 0.14 M
• Catalyst- HF- 0.8 to 1.6M
• Solvent- Ethanol
• Water
Chemicals
• Hemp stems
• Hemp residue
Material
Nanosol variants, composition and post-processing temperature
80

Morphological
changes
• SEM
Chemical
compositions
• EDX
81

Fig 25. SEM micrographs of hemp fibers modified by sol TEOS 0.09 M, HF 0.8 M (Sol variant
a)
Fig 26. EDX spectra of hemp
fibers modified by sol TEOS
0.09 M, HF 0.8 M (Sol
variant a)
82

Fig 27. SEM micrographs of hemp fibers modified by sol TEOS 0.13 M, HF 0.8 M (Sol variant b)
83
Fig 28. EDX spectra of hemp fibers modified by sol TEOS 0.13 M, HF 0.8 M (Sol variant b)

Fig 29. SEM micrographs and EDX spectra of hemp fibres modified by sol TEOS 0.14 M, HF 1.6 M (Sol
variant c1)
Fig 30. SEM micrographs of hemp residues modified by sol TEOS 0.14 M, HF 1.6 M (Sol variant c2)
84

Fig 31. Hemp fibres 50 wt% composite Et, σmax, HV
85
Microhardness= HV
Modulus of elasticity in tension= Et
Tensile strength= σmax Surface

Conclusion
86
• Matrix-filler compatibility
• Mechanical property
• Better adhesion

Statistical Optimization of the Sol–Gel Electrospinning Process
Conditions for Preparation of Polyamide 6/66 Nanofiber
Bundles
• To statistically optimise the production and characterisation of
polyamide 6/66 (PA 6/66) nanofiber obtained through sol-gel method
Franco et al, 2018
88
Article - 9

• PA 6/66
• Solvent- Formic acid and acetic acid
• Coagulation bath- Distilled water
Materials
• Conc- 12%wt, 17% wt, and 22% wt
• Continuous stirring at room temperature
Preparation of Polyamide
Solutions
• Voltage- 27.5 kV
• Metal needle placed at 12 cm from the collector
• Flow of the solution was controlled by a syringe pump
Electrospinning Sol–Gel
Process
89

Fig 32. Electrospinning sol–gel process
• Nanofiber bundles of PA 6/66 , (12, 17, and
22%), following a unifactorial design
completely random with 3 replicas and a
significance level of α = 0.05
Statistical
optimisation
• Productivity in the deposit of nanofibers
• Draw ratio
• Nanofiber bundle tensile strength
Variables
90

Phase transitions
DSC ASTM D3418-08
Tensile strength
EZ-Test L ASTM D3822
Morphology
SEM JEOL JSM 6490 LV, Japan
91

Fig 34. Draw ratio of the
electrospinning sol–gel process
Fig 33. Productivity of the basic
electrospinning process
92

Fig 35. SEM images of PA 6/66 electrospun nanofibers at different concentrations
a) 12% wt., b) 17% wt., and c) 22% wt
Fig 36. SEM images of polyamide 6/66 nanofiber bundles obtained through electrospinning
sol–gel process at different concentrations
a) 12% wt., b) 17% wt., and c) 22% wt
93

Samples Tg (°C) Tm (°C) ΔHm (J/g) Xc (%)
PA 6/66 51.33 192.80 74.16 39.45
Nanofibers 17% 35.93 186.28 23.13 12.30
Nanofiber bundles 17% 40.29 190.79 33.47 17.80
Table 12. Thermal parameters obtained by DSC results
94
Fig 37. Tensile strength of polyamide 6/66 nanofiber bundles at different concentrations
Glass-transition temperature
(Tg)
Melting temperature (Tm)
Heat of fusion (ΔHm)
Degree of crystallinity (Xc)

Conclusion
95
• 6/66 polyamide electrospinning
sol–gel process- (17%
concentration)
• High productivity
• Better draw ratio
• Good tensile strength

Synthesis of a Novel Nanoencapsulated n-Eicosane Phase Change Material
with Inorganic Silica Shell Material for Enhanced Thermal Properties
through Sol-Gel Route
• To develop a novel inorganic encapsulation technique for PCMs to
enhance their performance in heat energy storage and thermal
regulation
• To investigate the formation mechanism of these silica nanocapsules
Mohy et al, 2017
97
Article - 10

Tetraethyl
orthosilicate
Sodium
silicate
Hydrochloric
acid
n-Eicosane
PEO-PPO-
PEO
Materials
Synthesis of capsule 98
• TEOS/ Sodium silicate
• W/O emulsion with HCl
Hydrolysis/
condensation
• PEO-PPO-PEO (0.25 g) was dissolved in 150 ml deionized water at
55°C, n-eicosane (15 g) stirred for 3 h
• TEOS (15 g), HCl added- drop wise, stirred at 35°C
• Silica-sol was added drop wise into the prepared emulsion and
kept it stirring for 24 h
TEOS derived
nanoencapsul
ation
• PEO-PPO-PEO (0.5 g) was dissolved in 250 ml deionized water at
70°C, n-eicosane (10 g) stirred for 1 h
• Sodium silicate (5 g), HCl added- drop wise, stirred at 35°C
• Silica-sol was added drop wise into the prepared emulsion and
kept it stirring for 24 h, heating 70°C
Sodium
silicate
derived
nanoencapsul
ation
• Washed- ethanol, dried at 50°C overnight
Removal of
sufactant

Fig 38. Schematic diagram of nano-encapsulated n-eicosane PCM with silica shell via sol-
gel process
99

Characterization
Morphologies- Scanning Electron Microscope
(SEM, SU1510)
Fourier transform infrared (FTIR) spectra-
Nicolet iS10 FT-IR spectrometer
PCD- Differential Scanning Calorimetry
instrument (DSC-Q200)
Thermogravimetric analysis (TGA)- heating
rate of 10°C/min
100

Fig 39. SEM images of nanocapsules synthesized at different pH values and by using
TEOS/sodium silicate as a silica-precursors:
(a and b) n-eicosane/TEOS at pH 2.20;
(c and d) n-eicosane/TEOS at pH 1.88; (e and f) n-eicosane/sodium silicate at pH2.94
101

Fig 40. Particle size distribution plots of the nanoencapsules synthesized at different pH
values and silica precursors: (a,c,d) n-eicosane/TEOS; (b & e) n-eicosane/ sodium silicate
102

Fig 41. FTIR spectra of bulk and nanoencapsulated n-eicosane synthesized at different pH values and
silica-precursors: (a) n-eicosane/TEOS; (b) n-eicosane/sodium silicate
103
Fig 42. DSC thermograms of the bulk and nanoencapsulated n-eicosane synthesized under different
conditions, the curve numbers correspond to the samples code
Samp
le
code
N Eicosane/
Silica precursor
ratio (wt/wt)
pH
1 100/0 -
2 50/50 (TEOS) 2.25
3 50/50 (TEOS) 1.88
4 50/50 (TEOS) 2.2
5 50/50 (S.S) 2.94
6 50/50 (S.S) 2.5

Fig 43. Digital photographs:
(a) n-eicosane/silica
nanopasules; (b) pure n-
eicosane heated at hot stage
from room temperature to
60°C
104
Fig 44. TGA (a) and (b) DGA thermograms of silica-nanoencapsulated n-eicosane
synthesized under different conditions, the curve numbers correspond to the samples
code
Samp
le
code
N Eicosane/ Silica
precursor ratio
(wt/wt)
pH
1 100/0 -
2 50/50 (TEOS) 2.25
3 50/50 (TEOS) 1.88
4 50/50 (TEOS) 2.2
5 50/50 (S.S) 2.94
6 50/50 (S.S) 2.5

Conclusion
• Morphology- pH value
• Nanoencapsulated n-eicosane (TEOS)-
spherical morphologies at pH 2.20~2.30
• Good encapsulation efficeiency-TEOS
• High encapsulation rate and heat stability-
Sodium silicate
105

Reference
1. Ahlawat D. S., Kumari R., Rachana, Yadav I., 2014, Synthesis and characterization of sol-gel
prepared silver nanoparticles. Int. J. Nanosci., 13(1): 1-8.
2. Alwan R. M., Kadhim Q. A., Sahan K. M., Ali R., Mahdi R., Kassim N. and Jassim A., 2015,
Synthesis of zinc oxide nanoparticles via sol-gel route and their characterization. Nanosci.
Nanotech., 5(1): 1-6.
3. Ferri L. D., Lorenzi A., Carcano E. and Draghi L., 2016, Silk fabrics modification by sol-gel
method. Text. R. J., 88(1): 99-107.
4. Franco E., Dussan R., Amu M. and Navia D., 2018, Statistical optimization of the sol–gel
electrospinning process conditions for preparation of polyamide 6/66 nanofiber bundles.
Nanoscale Res. Letters, 671 (2018): 1-7.
5. Kale R., Agnihotri A. and Jagpat P. S., 2016, Simultaneous dyeing and anti-bacterial finishing of
textile by sol-gel technique. Adv. App. Sci. Res., 7(2):116-122.
6. Liu X., Lin T., Peng B. and Wang X., 2012, Antibacterial activity of capsaicin-coated wool
fabric. Text. R. J., 82(6): 584-590.
7. Mohy U. H. G, Jin Z. and Qufu W., 2017, Synthesis of a novel nanoencapsulated n-Eicosane
phase change material with inorganic silica shell material for enhanced thermal properties
through sol-gel route. J. Text. Sci. Eng., 7(2): 1-8.
8. Rosace G., Colleon C., Guido E. and Malucelli G., 2017, Phosphorus-silica sol-gel hybrid
coatings for flame retardant cotton fabrics. Tekstilec, 60(1): 29-35.
9. Xing Y. and Ding X., 2016, UV photo-stabilization of tetrabutyl titanate for aramid fibers via
sol–gel surface modification. J. App. Polymer Sci., 103(2016): 3113-3119.
10. Zelca Z., Kukle S. and Kajaks J., 2017, Hemp fibres modification by sol-gel method for
polyolefin composite filling. Procedia Eng. 200 (2017): 26-32.
106

Sol-gel technology for nano-textiles

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Sol-gel technology for nano-textiles

Similar to Sol-gel technology for nano-textiles (20)

Recently uploaded

Recently uploaded (20)

Sol-gel technology for nano-textiles

Editor's Notes